Small Engines (Lawn Mowers, etc.): advice on used mower, air filter element, oil change intervals

Question
I am looking at a Husqvarna zth 6125 with around 550 hours on it.  25HP 60in cut.

Is 550 hours high, what is expected life span of this type of mower.  Any any advice on making sure I don't get taken advantage of and making sure this is a quality used product that will last a few years.  I am buying it from a resellers not an individual.

Thanks,
Ryan

Answer
For a commercial piece of equipment 550 hours are low.  2000 is high hours.  But none of it matters if the maintenance was not done.  Ask about oil change intervals and how often they replaced the air filter element.  Was greasing done daily and how old is the hydro fluid.

Look at the oil it should be clean looking and not milky in color at all.  Run it for a while forward and reverse then look again.  Is it full of air bubbles?  If so there is an air leak on the low pressure side of the hydro motors.  Put the front end against a building and see if you can make the machine break traction, squeal the tires, it should.  Look at engine oil is it clean.  Take off the air filter element and inspect the air filter housing.  Where is the dirt?  Be sure it is on the outside of the element and not on the inside.  Deck spindles should be checked. Raise the deck all the way up and carefully reach under it and try to move the spindles up and sown.  Ask if they are rebuildable spindles.  If so there should be no play in the bearings.  If not there will be some but they are inexpensive. The rest is eye candy.  Hope I helped.